US2121192A

US2121192A - Lamp

Info

Publication number: US2121192A
Application number: US34918A
Authority: US
Inventors: Leo S Greenmun
Original assignee: DAYATNITE LAMP CORP
Current assignee: DAYATNITE LAMP Corp
Priority date: 1935-08-06
Filing date: 1935-08-06
Publication date: 1938-06-21
Anticipated expiration: 1955-06-21

Description

June 21, 1938. s GREENMUN 2,121,192

LAMP

Original Filed July 6, 1935 2 Sheets-Sheet} INVENTOR. i 60 67'667777ZZfZ ATTORNEYJ June 1938, L, s, GREENMUN 2,121,192

LAMP Original Filed July 6, 1955 2 Sheets-Sheet 2 INVENTOR.

69. 7 I 60 Grffzmarz 52 M ATTORNEY6 l Patented June 21, 1938 LAMP ,Leo S. Greenmum-Binghamton, N. Y., assignor to .DayatniteLamp Corporation, Newark, N. J.,-a corporation of Delaware Application August 6, 1935, Serial No. 34,918

' Renewed November 4, 1937 9 Claims,

This invention relates, as indicated, to lamps, :but has referencemore particularlyto incandescent lamps designed for use in connection with automobile headlamps and the like, and having incorporated therein means for controlling the forwardly'directe'd rays from the lamp filament soastowpreventglare and other ill effects by causing substantially all of these rays to be properlyredirected and projected as reflected rays which liein themain beam of the headlamp and assist in properly illuminating the roadway in advanceof the automobile.

In the co-pending application of'Harry A. Kotz, Serial No. 692,449, there'is 'disclosed'an incandescent lamp having incorporated thereon an auxiliary reflector which is designed to accomplish substantially the. same results as the auxiliary reflector to i be hereinafter described, but which is supported in advance of the lamp filament by means of wire arms, which are secured at'their. rearwends' to a metallic band, which is permanently secured to and embraces the glass filament-supporting element of the lamp.

It has been found in'practice that-when the auxiliary reflector is secured within the bulb in the aforesaid manner or is secured within the lamp'by means ofa wire or wires extending from the filament-supporting wires, that an electrostatic action'occurs. in which the current in the lampfilamentjumps the gap'between the filament'and'theiauxiliary reflector, carrying therelWilJh tungsten "dust'which is deposited upon the reflectoig'thereby greatly diminishing, if not destroying, the usefulness'of such reflector. Moreover, due to vagrant.electriccurrents which are set up in the reflector, an electronic discharge occurs which causes blackening of the lamp through the deposit on thewalls'of the lamp of dust which isreleased by this discharge.

If sufficient clearancebetween the filament and the auxiliary reflector is maintained so astoeliminate or diminish the aforesaid effects, then it becomes difiicult or impossible to control all of the stray or scattered forwardly directed filament a lamp having incorporated therein an auxiliary reflectorwhich is secured within the lamp in-such a manner that a considerable reduction in the number of parts required to support the reflector the proper positioning of the lamp filament with reference to thebase of the lamp.

To the accomplishment of the foregoingand related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed outin the claimsythe annexed 3 is a similar view of-another modification of the lamp; Fig.4 is a similar view of still another modification of the lamp; andFigs. 5, 6 and"? illustrate various stepsin the assembly of the lamp shown in Fig. 4.

Referring to said drawings, and-more particularly to Fig. 1, there is shown a fragment of an automobile headlamp ofthe fixed focus type embodying a parabolic main reflector- I having an axially disposed socket 2, within which is received the base3 of the lamp 4.

The filament 5 ofthe lamp is positioned at approximately the focus of the reflector.

The auxiliary reflector in this case comprises acircular member fiyof sheet metal or the like,

having its center in the focal axisof the reflector and its base 1 near the focal plane of the reflector l. The member '6 is provided with a forwardly extending flange 8 from which extends a plurality of circumferentially spaced fingers-9 which have i an inherent resiliency tending to force them radially outwardly and into engagement with an inwardly extending annular ridge l0 of the lamp bulb proper. Thefingers 9, it will be noted, are curved adjacent their forward ends to conform with the contour of the ridge H) and the forward end of the lamp.

The interior surface of the member 6, which is of a highly polished character, is a surface'of revolution generated by a compound curve, preferably a compound curve consisting of a parabola and a hyperbola, the parabola and hyperbola merging into each other to form a smooth continuous curve. Such a surface is disclosed in the Kotz application to which reference has been made, but it will be understood that the specific form of the auxiliary reflector is not of the essence of the present invention, and that other forms, such as a plain circular disk, may be employed, if desired.

It will be noted that the diameter of the member 6 is slightly less than the diameter of the opening at the base of the glass bulb. This enables the auxiliary reflector to be inserted into, and secured. in position within, the bulb during the assembling operations incident to the manufacture of the lamp.

With the reflector secured within the forward end of the lamp in the manner described, the electrostatic action and electronic discharges to which reference has been made are completely avoided as the spring fingers 9 which support the reflector are remote from both the filament and filament supporting wires, and the reflector retains its polished character for long periods. Moreover, the auxiliary reflector may be positioned sufliciently close to the focal plane of the main reflector to control all of the forwardly directed rays from the lamp filament, thereby preventing glare and other ill effects by causing substantially all of these rays to be properly redirected and projected as reflected rays which lie in the main beam of the headlamp and assist in properly illuminating the roadway in advance of the automobile.

In that form of the lamp shown in Fig. 2, the auxiliary reflector 6 consists of a disk of nickel having a forwardly extending flange or clip 8' whereby the disk is clipped or secured to the flared end of a glass cup 9'. The cup 9' is secured within the forwardly extending hollow tip 4 of the lamp, the glass cup and lamp being fused to each other during the assembling operations.

By supporting the auxiliary reflector within the lamp in the manner shown in Fig. 2, the amount of metal required for the reflector and its supporting elements is reduced to a' minimum, as the reflector disk may,-in this instance, be made of metal of extreme thinness, i. e., about .002" thick, and of pure nickel or a heat resisting alloy. This is of advantage because it is generally desirable to have as little metal within the lamp as possible. By reducing the cubic contents of the metal in the reflector to a minimum, the liberation of gases from such metal is avoided as well as heat and electrical radiations which release impurities from the metal.

In that form of the lamp shown in Fig. 3, a glass tube 20 is secured within the forwardly extending hollow tip 2| of the'lamp, the tube and lamp being fused to each other during the assembling operations. One end of the tube 20 is provided with a closure 22 which is integral with the tube and is of a cross-section similar to that of the member 6 in that form of the invention shown in Fig. 1. The interior surface of the closure 22 is coated with a material of a reflecting quality, such as silver, aluminum, etc.

In that form of the lamp shown in Fig. 4, a glass tube 30, similar to the tube 20, is provided and is secured within the forwardly extending hollow tip 3| of the lamp in the same manner that the tube and lamp in Fig. 3 are secured to each other. The tube is provided with a closure 32 which is similar to the closure 22 of the tube 20. Before assembling this tube with the lamp, a reflector disk 33 is provided, as shown in Fig. 5, this reflector disk being made of metal of a thinness and character similar to those of the reflector disk 6. This reflector disk is first inserted within the tube as shown in Fig. 6, and is forced into the position shown in Fig. 7 as by means of a tool 34. The tool 34 also presses the disk into a form which corresponds with the cross-section of the closure 32 and in so doing increases the diameter of the disk so as to cause the edges of the disk to enter the recess 35 at the junction of the tube and closure. The disk is thus securely locked in the desired position.

In those forms of the invention shown in Figs. 3 and 4, the reflector is within the lamp, but a body of glass is interposed between the filament and the reflector. This results in virtual elimination of the electrostatic and electronic effects hereinbefore referred to.

It will be further noted that the auxiliary reflectors in each case may be accurately located axially of the lamp, as they are, in effect, made a part of the bulb. This enables the reflector, during the assembling operations of the lamp, to be utilized as a target for accurately locating filament with respect to the base and locating pins of the lamp.

Other forms may be employed embodying the features of my invention instead of the one here explained, change being made in the form or construction, provided the elements stated by any of the following claims or the equivalent of such stated elements be employed.

I therefore particularly point out and distinctly claim as my invention:

1. An incandescent lamp having a circular reflector mounted therein in advance of the filament thereof, said reflector facing toward the base of said lamp, and means for supporting said reflector, said means extending from the annular edge of the reflector and into engagement with the walls of the lamp bulb.

2. An incandescent lamp having a circular reflector mounted therein in advance of the filament thereof and means integral with said reflector for supporting the same, said means extending from the annular edge of the reflector and into engagement with the Walls of the lamp bulb.

3. An incandescent lamp having a reflector mounted therein in advance of the filament thereof, and means for supporting said reflector, said means comprising a plurality of fingers extending from spaced points on the periphery of the reflector and into engagement with the Walls of the lamp bulb.

4. An incandescent lamp having a reflector mounted therein in advance of the filament thereof, said reflector facing towards the base of said lamp, and means for supporting said reflector, said means comprising a plurality of fingers extending from spaced points on the periphery of the reflector and into engagement with the walls of the lamp bulb.

5. An incandescent lamp comprising a bulb having a shoulder adjacent the front end of the bulb, a reflector mounted in said bulb in advance of the filament thereof, and means for supporting said reflector, said means comprising resilient fingers extending forwardly from the reflector and into engagement with said shoulder.

6. An incandescent lamp comprising a bulb having an inwardly extending annular ridge adjacent the front end of the bulb, a reflector mounted in said bulb in advance of the filament thereof, and means for supporting said reflector, said means comprising resilient fingers extending forwardly from the reflector and into locking engagement with said ridge.

'7. An incandescent lamp having a circular reflector disposed therein in advance of the filament thereof, and means for supporting said reflector, said means comprising a cup-like member extending forwardly from the annular edge of the reflector and into engagement with the walls of the lamp bulb. v

8. An incandescent lamp having a circular reflector disposed therein in advance of the filament thereof, and means for supporting said reflector, said means comprising a cup-like member of glass extending from the annular edge of the reflector to the front end of the lamp bulb.

9. An incandescent lamp comprising a bulb having a forwardly projecting tubular tip portion, a circular reflector disposed in said bulk) in advance of the filament thereof, and means for supporting said reflector, said means comprising a tubular member of glass or the like extending from the annular edge of said reflector and into said tip portion of the bulb.

LEO S. GREENMUN.